Novel ABA triblock and diblock copolymers and methods of preparing the same

ABSTRACT

The invention discloses a method for preparing a triblock copolymer of the formula:  
                 
 
     comprising:  
     (a) contacting a cycloalkene with a chain transfer agent of the formula:  
     Z—Y═Y—Z  
      in the presence of a metal carbene metathesis catalyst to form a telechelic polymer; and  
     (d) contacting the telechelic polymer with an alkene of the formula  
                 
 
      in the presence of an ATRP organometallic catalyst  
     wherein n and m are integers; Z is an ATRP initiator and —Y═Y— is an alkenyl group; and, R′ is selected from the group consisting of aryl, nitrile and C 1 -C 20  carboxylate, wherein R′ is substituted or unsubstituted. The invention also discloses a method for preparing a diblock copolymer. In addition, the invention encompasses a triblock copolymer having no 1,2-PBD structure in the PBD portion of the copolymer.

[0001] This application claims the benefit of U.S. Provisional PatentApplication Serial No. 60/124,915, filed Mar. 18, 1999, the contents ofwhich are herein incorporated by reference in its entirety.

[0002] The U.S. Government has certain rights in this invention pursuantto Grant No. 9509745 awarded by the National Science Foundation.

BACKGROUND

[0003] Recently, great attention has been directed toward the synthesisof ABA triblock copolymers that function as thermoplastic elastomers.These materials are composed of long blocks of different homopolymerspossessing incompatible aggregation behavior. Generally, two blocks arestructurally rigid and dispersed in the form of minute glassy domains ina third block, usually a flexible polymer possessing an amorphous,rubbery phase. For example, FIG. 1 shows a schematic representation ofthe microphase behavior of SBS triblock copolymers, showing areas ofaggregation of the glassy poly(styrene) blocks, dispersed in theamorphous poly(butadiene) chains. The glassy regions serve as anchorsthat hold the soft, elastomeric domains together in a network structureand effectively behave as crosslink points, eliminating the need tovulcanize the material. Heating thermoplastic materials above themelting (“T_(m)”) or glass transition temperature (“T_(g)”) of the“hard” blocks softens the glassy domains and allows the copolymer toflow; while cooling returns the phase separation and the material againbehaves as a crosslinked elastomer.

[0004] Poly(styrene)-b-poly(butadiene)-b-poly(styrene) (“SBS”) triblockcopolymers are well-known thermoplastic elastomers. While their tensilestrength properties are similar to that of natural rubber, they aredependent on a high degree of 1,4-over 1,2-poly(butadiene) chainmicrostructure for optimal elastomeric behavior.

[0005] The most common synthesis of SBS involves a sequential additionanionic polymerization method (Scheme 1), which inherently introducesvarying degrees of 1,2-poly(butadiene) content into the polymerbackbone.

[0006] The useful service temperature range of SBS triblock copolymersis ultimately determined by the melting temperature of the poly(styrene)(“PS”) domains. It has been shown that the strength of these SBSpolymers drops sharply above 60° C. as the T_(g) of the PS domains isapproached. The use of end-blocks with a higher thermal resistance mightprovide a valuable answer to this problem. A potential candidate ispoly(methyl methacrylate) (“PMMA”) since it exhibits a T_(g) of ca. 130°C. (when its syndiotactic content reaches 80%).

[0007] Unfortunately, the synthesis of poly(methylmethacrylate)-b-poly(butadiene)-b-poly(methyl methacrylate) (“MBM”)triblock copolymers is not as straightforward as SBS. A key problem isthe inability of poly(methyl methacrylate) anions to initiate thepolymerization of butadiene. Since butadiene anions are sufficientlynucleophilic enough to react with methyl methacrylate, attention hasbeen directed towards the synthesis and use of difunctional initiators.However, this has resulted in marginal success and only recently havewell-defined MBM triblock copolymers been synthesized. Unfortunately,these copolymers display a high content 1,2-poly(butadiene)microstructure content (>45%) and thus exhibit poor elastomericproperties.

[0008] As a result, a need exists for a synthetic methods which wouldallow the synthesis of such ABA triblock copolymers such as poly(methylmethacrylate)-b-poly(butadiene)-b-poly(methyl methacrylate) whichexhibit good elastomeric properties.

SUMMARY

[0009] The present invention relates to novel ABA triblock co-polymersthat function as thermoplastic elastomers and methods for preparing thesame. In general, the inventive ABA triblock polymers are prepared usinga ring opening metathesis polymerization (“ROMP”) reaction followed byan atom transfer radical polymerization (“ATRP”) reaction. As it will befurther disclosed below, this tandem approach allows for the synthesisof novel ABA triblock polymers which were not previously possible usingprior art techniques. Briefly, ROMP is used to synthesize a telechelicpolymer with end groups which function as ATRP initiators in thefollowing manner:

[0010] wherein:

[0011] n is an integer;

[0012] is a cycloalkene;

[0013] Z—Y═Y—Z is a chain transfer agent wherein Z is a end group whichfunctions as a ATRP initiator and —Y═Y— is an alkenyl group; and,

[0014] is the resulting telechelic polymer.

[0015] The ROMP reaction is followed by a ATRP reaction wherein the ROMPtelechelic polymer product is further polymerized in the followingmanner:

[0016] wherein:

[0017] m is an integer;

[0018] is an alkene; and

[0019] is the resulting ABA copolymer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a schematic representation of the microphase behavior ofSBS triblock copolymers showing areas of aggregation of the glassy PSblocks dispersed in the amorphous PBD chains.

[0021]FIG. 2 is a typical GPC trace of telechelic PBD 2 and SBS triblockcopolymer prepared via ATRP of styrene initiated with 2.

[0022]FIG. 3 is a ¹H NMR spectra of telechelic PDB 2 and SBS triblockcopolymers synthesized by a tandem ROMP-ATRP approach.

[0023]FIG. 4 illustrates the kinetic behavior of ATRP of styrene at 130°C.

[0024]FIG. 5 illustrates the molecular weight and PDI dependence onmonomer conversion for ATRP of styrene initiated with 2 using CuBr andCuCl catalysts.

[0025]FIG. 6 illustrates the molecular weight distribution of MBMtriblock copolymers obtained by ATRP of MMA using 2.

[0026]FIG. 7 illustrates the kinetics of the ATRP of MMA initiated with2 using CuCl and CuBr catalysts.

[0027]FIG. 8 shows typical GPC traces of PBD 9 and MBM synthesized byATRP of MMA initiated with 9.

[0028]FIG. 9 is a ¹H NMR spectra of telechelic PDB 9 and MBM triblockcopolymers synthesized by a tandem ROMP-ATRP approach.

[0029]FIG. 10 illustrates the kinetics of the ATRP of MMA initiated by 9catalyzed by CuCl at 100° C. in Ph₂O.

[0030]FIG. 11 illustrates the molecular weight and PDI dependence onmonomer conversion for ATRP of MMA initiated by 9 using CuCl catalyst.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present invention relates to novel ABA triblock co-polymersthat function as thermoplastic elastomers and methods for preparing thesame. In general, the inventive ABA triblock polymers are prepared usingring opening metathesis polymerization (“ROMP”) reaction followed byatom transfer radical polymerization (“ATRP”) reaction. This tandemapproach allows for the synthesis of novel ABA triblock polymers whichwere not previously possible using conventional techniques.

[0032] Atom Transfer Radical Polymerization (“ATRP”)

[0033] One of the most successful strategies for controlled free radicalpolymerization is ATRP, first reported independently by Sawarnato andMatyjaszewski. The mechanism of ATRP is outlined in Scheme 2 and isbased on a reversible, metal mediated halide exchange process.

[0034] Control is achieved because the relative rates of activation anddeactivation (i.e., the equilibrium constant) is on the order of 10⁻⁷.Thus, the concentration of growing radicals is sufficiently low (ca.10⁻⁸M) to effectively eliminate bimolecular termination. PS and PMMAwith pre-determined molecular weights and low (1.05 to 1.50)polydispersity indices (“PDIs”) have been obtained using ATRP. Copperchloride and 2,2°-bipyridine (“bipy”) are often employed as theorganometallic catalyst in these polymerizations.

[0035] Thermoplastic elastomers using n-butyl acrylate, methyl acrylate,or 2-ethylhexyl acrylate as the soft B block with styrene, methylmethacrylate, or acrylonitrile comprising the hard A blocks have beenprepared. Typically, difunctional ATRP initiators were used tosynthesize the central B block, followed by addition of a second monomerto form the two A blocks. Unfortunately, the elastomeric properties ofthese copolymers have been relatively inferior to SBS or MBM copolymers.Due to the instability of the butadiene radical, SBS, MBM or anypoly(butadiene) containing block copolymer may not be readilysynthesized using this method.

[0036] In an effort to overcome this limitation, there have beenattempts to integrate ATRP with other polymerization methods. Forexample, Scheme 3 illustrates one such approach.

[0037] Although this approach was successful for preparing diblockcopolymers such as poly(styrene)-b-poly(norbornene) and poly(methylacrylate)-b-poly(norbornene), the synthesis of triblock copolymersrequires a polymer with initiating groups on both ends.

[0038] Telechelic Polymers via Ring-Opening Metathesis Polymerization(ROMP)

[0039] Telechelic polymers are polymers that possess functionalend-groups capable of further reactivity. One versatile approach to thesynthesis of telechelic polymers involves the ROMP of a cyclic olefinmonomer in the presence of an acyclic functionalized alkene that behavesas a chain transfer agent (“CTA”). The general mechanism for thisprocess is outlined in Scheme 4.

[0040] Propagating polymer chains react with a CTA that effectivelytransfers the active growing species. This results in a polymeric chainand a new metal carbene each containing a functional group from the CTA.The new metal carbene can then react with either monomer (producing anew polymer chain) or a preformed polymer chain (transferring the activespecies). The only polymer endgroups that do not contain functionalgroups originating from the CTA are those from the initiating metalcarbene and the terminating agent, which in principle, can be chosen tomatch those of the CTA. In absence of any termination reactions, thenumber of active centers is preserved, and can lead to telechelicpolymers with a number averaged degree of functionality (“F_(n)”) thatapproaches 2.0.

[0041] The combination of ruthenium-based ROMP initiators and a varietyof CTA's have resulted in the synthesis of a large number of telechelicpolymers (Scheme 4).

[0042] Tandem ROMP-ATRP Approach

[0043] The present invention combines ROMP and ATRP in a novel strategyfor the synthesis of copolymers, in particular triblock and diblockcopolymers. In general, ROMP is used to synthesized a telechelic polymerwith end groups which function as ATRP initiators in the followingmanner:

[0044] wherein:

[0045] n is an integer;

[0046] is a cycloalkene;

[0047] Z—Y═Y—Z is a chain transfer agent wherein Z is a end group whichfunctions as a ATRP initiator and —Y═Y— is an alkenyl group; and,

[0048] is the resulting telechelic polymer.

[0049] The ROMP reaction is followed by a ATRP reaction wherein the ROMPtelechelic polymer product is further polymerized in the followingmanner:

[0050] wherein:

[0051] m is an integer;

[0052] R′ is an alkene; and

[0053] is the resulting ABA copolymer.

[0054] Similarly, a diblock copolymer can be synthesized by changing oneof the Z groups to a Z′ group, where Z′ does not act as an ATRPinitiator. In general, ROMP is used to synthesized a telechelic polymerwith only one end group which functions as ATRP initiator in thefollowing manner:

[0055] wherein:

[0056] n is an integer;

[0057] is a cycloalkene;

[0058] Z—Y═Y—Z′ is a chain transfer agent wherein Z is a end group whichfunctions as a ATRP initiator and —Y═Y— is an alkenyl group; and,

[0059] is the resulting telechelic polymer.

[0060] The ROMP reaction is followed by a ATRP reaction wherein the ROMPtelechelic polymer product is further polymerized in the followingmanner:

[0061] wherein:

[0062] m is an integer;

[0063] is an alkene; and

[0064] is the resulting diblock copolymer.

[0065] In these cases, Z′ can be any group that does not function as anATRP initiator. For example, Z′ can be a moiety selected from the groupconsisting of hydrogen or one of the following substituent groups:C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, aryl, C₁-C₂₀ carboxylate,C₁-C₂₀ alkoxy, C₂-C₂₀ alkenyloxy, C₂-C₂₀ alkynyloxy, aryloxy, C₂-C₂₀alkoxycarbonyl, C₁-C₂₀ alkylthio, C₁-C₂₀ alkylsulfonyl and C₁-C₂₀alkylsulfinyl. Optionally, the substituent group may be substituted withone or more groups selected from C₁-C₅ alkyl, C₁-C₅ alkoxy, and aryl.When the substituent aryl group is phenyl, it may be further substitutedwith one or more groups selected from a halogen, a C₁-C₅ alkyl, or aC₁-C₅ alkoxy. Moreover, Z′ may further include one or more functionalgroups. Examples of suitable functional groups include but are notlimited to: hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether,amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate,isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen. Furtherdiscussion on this approach can be found in Bielawski, C. W.; Morita,T.; Grubbs, R. H. Macromolecules 2000, 33, 678, the contents of whichare herein incorporated by reference.

[0066] ROMP Initiators

[0067] In general, initiators (or catalysts) that may be used in thepractice of the present invention are ruthenium or osmium carbenecomplexes that include a ruthenium or osmium metal center that is in a+2 oxidation state, have an electron count of 16, and arepenta-coordinated. More specifically, the initiators are of the formula

[0068] wherein:

[0069] M is ruthenium or osmium;

[0070] X and X¹ are independently any anionic ligand;

[0071] L and L¹ are any neutral electron donor ligand;

[0072] R and R¹ are each hydrogen or one of the following substituentgroups: C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, aryl, C₁-C₂₀carboxylate, C₁-C₂₀ alkoxy, C₂-C₂₀ alkenyloxy, C₂-C₂₀ alkynyloxy,aryloxy, C₂-C₂₀ alkoxycarbonyl, C₁-C₂₀ alkylthio, C₁-C₂₀ alkylsulfonyland C₁-C₂₀ alkylsulfinyl. Optionally, the substituent group may besubstituted with one or more groups selected from C₁-C₅ alkyl, C₁-C₅alkoxy, and aryl. When the substituent aryl group is phenyl, it may befurther substituted with one or more groups selected from a halogen, aC₁-C₅ alkyl, or a C₁-C₅ alkoxy. Moreover, the initiator may furtherinclude one or more functional groups. Examples of suitable functionalgroups include but are not limited to: hydroxyl, thiol, thioether,ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylicacid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy,carbamate, and halogen.

[0073] These ruthenium and osmium carbene complexes have been describedin U.S. Pat. Nos. 5,312,940, 5,342,909, 5,710,298, and 5,831,108 and PCTPublication No. WO 98/21214, all of which are incorporated herein byreference.

[0074] In preferred embodiments of these catalysts, the R substituent ishydrogen and the R¹ substituent is selected from the group consistingC₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, and aryl. In even more preferredembodiments, the R¹ substituent is phenyl or vinyl, optionallysubstituted with one or more moieties selected from the group consistingof C₁-C₅ alkyl, C₁-C₅ alkoxy, phenyl, and a functional group. Inespecially preferred embodiments, R¹ is phenyl or vinyl substituted withone or more moieties selected from the group consisting of chloride,bromide, iodide, fluoride, —NO₂, —NMe₂, methyl, methoxy and phenyl. Inthe most preferred embodiments, the R¹ substituent is phenyl.

[0075] In preferred embodiments of these catalysts, L and L¹ are eachindependently selected from the group consisting of phosphine,sulfonated phosphine, phosphite, phosphinite, phosphonite, arsine,stibine, ether, amine, amide, imine, sulfoxide, carboxyl, nitrosyl,pyridine, and thioether. In more preferred embodiments, L and L¹ areeach a phosphine of the formula PR³R⁴R⁵, where R³, R⁴, and R⁵ are eachindependently aryl or C₁-C₁₀ alkyl, particularly primary alkyl,secondary alkyl or cycloalkyl . In the most preferred embodiments, L andL¹ ligands are each selected from the group consisting of—P(cyclohexyl)₃, —P(cyclopentyl)₃, —P(isopropyl)₃, and —P(phenyl)₃.

[0076] In preferred embodiments of these catalysts, X and X¹ are eachindependently hydrogen, halide, or one of the following groups: C₁-C₂₀alkyl, aryl, C₁-C₂₀ alkoxide, aryloxide, C₃-C₂₀ alkyldiketonate,aryldiketonate, C₁-C₂₀ carboxylate, arylsulfonate, C₁-C₂₀alkylsulfonate, C₁-C₂₀ alkylthio, C₁-C₂₀ alkylsulfonyl, or C₁-C₂₀alkylsulfinyl. Optionally, X and X¹ may be substituted with one or moremoieties selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₁₀alkoxy, and aryl which in turn may each be further substituted with oneor more groups selected from halogen, C₁-C₅ alkyl, C₁-C₅ alkoxy, andphenyl. In more preferred embodiments, X and X¹ are halide, benzoate,C₁-C₅ carboxylate, C₁-C₅ alkyl, phenoxy, C₁-C₅ alkoxy, C₁-C₅ alkylthio,aryl, and C₁-C₅ alkyl sulfonate. In even more preferred embodiments, Xand X¹ are each halide, CF₃CO₂, CH₃CO₂, CFH₂CO₂, (CH₃)₃CO,(CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO, MeO, EtO, tosylate, mesylate, ortrifluoromethanesulfonate. In the most preferred embodiments, X and X¹are each chloride.

[0077] The most preferred initiators in the practice of the presentinvention are as described above wherein M is ruthenium; X and X¹ areboth chloride; L and L¹ ligands are both —P(cyclohexyl)₃; R is hydrogen;and R¹ is either phenyl, (—CH═CPh₂), or (CH═C(CH₃)₂).

[0078] The above initiators/catalysts are stable in the presence of avariety of functional groups including hydroxyl, thiol, ketone,aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid,disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, andhalogen. Therefore, the starting materials and products of the reactionsdescribed below may contain one or more of these functional groupswithout poisoning the catalyst. In addition, the initiators are stablein the presence of aqueous, organic, or protic solvents, includingaromatic hydrocarbons, chlorinated hydrocarbons, ethers, aliphatichydrocarbons, alcohols, water, or mixtures of the above.

[0079] ROMP Cycloalkene

[0080] Any cycloalkene (also referred to as cyclic olefin) that canparticipate in a ring-opening metathesis polymerization (“ROMP”)reaction may be used. Because of the generally high metathesis activityof the initiators of the present invention, the cycloalkene may bestrained or unstrained. In addition, the cycloalkene may be substitutedor unsubstituted and may include one or more substituent groups selectedfrom the group consisting of C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, aryl, C₁-C₂₀ carboxylate, C₁-C₂₀ alkoxy, C₂-C₂₀ alkenyloxy,C₂-C₂₀ alkynyloxy, aryloxy, C₂-C₂₀ alkoxycarbonyl, C₁-C₂₀ alkylthio,C₁-C₂₀ alkylsulfonyl and C₁-C₂₀ alkylsulfinyl, wherein each of thesubstituents may be substituted or unsubstituted.

[0081] Optionally, the substituent group is substituted with one or moresubstituted or unsubstituted moieties selected from the group consistingof C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, and aryl. The moiety, in turn, may besubstituted with one or more groups selected from the group consistingof halogen, C₁-C₅ alkyl, C₁-C₅ alkoxy. Further, the substituent may befunctionalized with a moiety selected from the group consisting ofhydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine,imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate,carbodiimide, carboalkoxy, carbamate, and halogen.

[0082] Illustrative examples of suitable cycloalkenes include but arenot limited to: norbornene, norbornadiene, cyclopentene,dicyclopentadiene, cyclo-octene, 7-oxanorbornene, 7-oxanorbornadiene,cyclodocene, 1,3-cyclooctadiene, 1,5-cyclooctadiene,1,3-cycloheptadiene, and derivatives thereof. In preferred embodiments,the cycloalkene is a cycloalkadiene. In more preferred embodiments, thecycloalkene is selected from the group consisting of norbornadiene,dicyclopentadiene, 1,3-cyclo-octadiene, 1,5-cyclo-octadiene,1,3-cycloheptadiene, and derivatives thereof. The use of1,5-cyclo-octadiene as the cycloalkene is most preferred.

[0083] ROMP Chain Transfer Agent

[0084] The chain transfer agent (“CTA”) is of the general formula,Z—Y═Y—Z, wherein —Y═Y— is an alkenyl group and Z is any end group whichis capable of functioning as an ATRP initiator. In preferredembodiments, —Y═Y— is a C_(2-C) ₂₀ alkene and Z is either chloride,bromide, allyl chloride, allyl bromide, 2-chloroisobutyrate, 2-bromoisobutyrate, 2-chloro proprionate, 2-bromo proprionate, 2-chloroacetate, 2-bromo acetate, o-, m-, or p-benzyl chloride, o-, m-, orp-benzyl bromide, o-, m-, or p-C₁-C₂₀ alkyl benzyl chloride, o-, m-, orp-C₁-C₂₀ alkyl benzyl bromide, p-toluenesulfonyl chloride,p-toluenesulfonyl bromide, trichloromethyl, tribromomethyl,dichloromethyl, and dibromomethyl. There are also several aryl, nitrile,and halogenated related initiators that may be used in the invention.For example, several ATRP initiators that have been discussed in U.S.Pat. Nos. 5,945,491, 5,910,549, 5,807,937, 5,789,487, and 5,763,548 toMatyjaszewski, the contents of which are incorporated herein byreference, may be used in accordance with the invention. ATRP initiatorsare also listed in Matyjaszewski, Ed; Controlled Radical Polymerization,ACS Symposium Series #685, American Chemical Society, Washington D.C.1998, the contents of which are incorporated herein in their entiretiesby reference. In more preferred embodiments, Z—Y═Y—Z is1,4-dichloro-cis-2-butene, bis(2-bromo isobutryate), or bis(2-bromoproprionate).

[0085] ATRP Organometallic Catalysts

[0086] Any suitable organometallic catalysts may be used in the practiceof the present invention. Preferably, the organometallic catalystfollows the general formula of MX_(p)L_(q) where M is ruthenium, copper,iron, or nickel; X is bromide or chloride, and L is selected from thegroup consisting of phosphine, sulfonated phosphine, phosphite,phosphinite, phosphonite, arsine, stibine, ether, amine, amide, imine,sulfoxide, carboxyl, nitrosyl, pyridine, and thioether; and wherein pand q are integers. In addition, L may be a phosphine of the formulaPR³R⁴R⁵, where R³, R⁴, and R⁵ are each independently aryl or C₁-C₁₀alkyl, particularly primary alkyl, secondary alkyl or cycloalkyl . Forexample, L may be selected from the group consisting of —P(cyclohexyl)₃,—P(cyclopentyl)₃, —P(isopropyl)₃, and —P(phenyl)₃.

[0087] Illustrative examples of suitable catalysts include but are notlimited to: CuCl/bipy; CuBr/bipy, CuCl/4-4′-di-n-heptyl-2,2′-bipyridine;CuBr/4-4′-di-n-heptyl-2,2′-bipyridine; FeCl₂/(PPh₃)₃; RuCl₂(PPh₃)₃;NiBr₂(PPh₃)₂; NiBr₂(Pn-Bu₃)₂, FeBr₂(Pn-Bu₃)₂, RuBr₂(Pn-Bu₃)₂. Otherpreferable examples include CuCl/tris[2-dimethylamino)ethyl]amine,CuBr/tris[2-dimethylamino)ethyl]amine,CuCl/1,4,8,11-tetramethyl-1,4,8-tetracyclotetradecane,CuBr/1,4,8,11-tetramethyl-1,4,8-tetracyclotetradecane,CuCl/N,N-bis(2-pyridylmethyl)octylamine, CuBr/N,N-bis(2-pyridylmethyl)octylamine, CuCl/tris[(2-pyridyl)methyl]amine,CuB r/tris[(2-pyridyl)methyl]amine,CuCl/N,N,N′,N′,N′-pentamethyidiethylenetriamine,CuBr/N,N,N′,N′,N′-pentamethyidiethylenetriamine,CuCl/1,1,4,7,10,10-hexamethyltriethylenetetraamine,CuBr/1,1,4,7,10,10-hexamethyltriethylenetetraamine,CuCl/tetramethylethylenediamine, and CuBr/tetramethylethylenediamine.Other catalysts that may be used in accordance with the invention can beseen in Macromolecules, 1998, 31, 5958-5959; Mircea and Matyjaszewski,Macromolecules, 2000; Macromolecules, 1999, 32, 2434-2437, the contentsof each of which are incorporated herein by reference. Because triblockand diblock polymers with predictable molecular weights and lowpolydispersity were consistently synthesized using these systems, theuse of CuCl/bipy or CuCl/4-4′-di-n-heptyl-2,2′-bipyridine is especiallypreferred.

[0088] Metal Carbene Metathesis Catalyst used for both ROMP and ATRP

[0089] Another aspect of the invention provides for the synthesis oftriblock copolymers without the use of an additional ATRP organometalliccatalyst. In other words, while the tandem ROMP/ATRP approach discussedabove would be followed, no additional ATRP organometallic catalyst isused. Recently, it has been shown that catalysts effective for ROMP arealso effective for ATRP. Thus, at the conclusion of the ROMP reaction,no additional catalyst would be added to initiate the ATRP.

[0090] Ethyl vinyl ether has been shown to be a reagent useful in thetermination of ROMP reactions. Particularly preferred is the ROMPcatalyst formed for use in ATRP after a vinyl ether is added toterminate the ROMP. In the example shown below, the ethyl vinyl etherreacts with the metal carbene initiator (or any derivative thereof,where R is hydrogen and R¹ is phenyl or any polymer chain) and forms anew metal species (R² is —OEt). While the new species is inactive inROMP, it is active in ATRP. Thus, in the synthesis of triblockcopolymers described above, at any given point during the ROMP reaction,ethyl vinyl ether can be added to terminate the ROMP reaction. Once theATRP monomer is added, ATRP is initiated and catalyzed by this newspecies

[0091] Further discussion on using metathesis catalysts as ATRPcatalysts can be found in, for example, Simal, F.; Demonceau, A.; NoelsA. F. Tetrahedon Lett. 1999, 40, 5689 and Simal, F.; Demonceau, A.;Noels A. F. Angew Chem 1999, 38, 538, the contents of both of which areherein incorporated by reference in their entireties.

[0092] ATRP Monomer

[0093] The ATRP monomer,

[0094] may be any suitable alkene (also referred to as an olefin)wherein R′ is an aryl or nitrile or C₁-C₂₀ carboxylate optionallysubstituted with one or more substituents such as C₁-C₅ alkyl, C₁-C₅alkoxy, and aryl. When the substituent aryl group is phenyl, it may befurther substituted with one or more groups selected from a halogen, aC₁-C₅ alkyl, or a C₁-C₅ alkoxy. Moreover, the ATRP monomer may furtherinclude one or more functional groups. Examples of suitable functionalgroups include but are not limited to: hydroxyl, thiol, thioether,ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylicacid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy,carbamate, and halogen. Illustrative examples of suitable monomersinclude styrene, methyl methacrylate, n-butyl acrylate, methyl acrylate,2-ethylhexyl acrylate, acrylonitrile, 4-vinylpyridine and glycidylacrylate. Because the ATRP polymerization is typically used tosynthesize the more structurally rigid polymer portions, the use ofmonomers such as styrene, methyl methacrylate and acrylonitrile isgenerally preferred.

[0095] Practice of the present invention generally results in a ABAtriblock copolymer of the general formula

[0096] wherein n, m, R′, and Z are as previously defined. The inventivesynthetic method is surprisingly robust and typically may be synthesizedin a one pot method. Even copolymers such as poly(methylmethacrylate)-b-poly(butadiene)-b-poly(methyl methacrylate) may bereadily synthesized. Scheme 5 illustrates one preferred embodiment ofthe inventive method.

[0097] In another surprising and unexpected result, the inventivesynthetic methods for the B portion of the copolymer results in apredominantly linear polymer. For example, when cyclo-octadiene is theROMP cycloalkene, a perfect 1,4-PBD microstructure is observed. Becauseof the absence of the 1,2-PBD structure which necessarily results withprior art methods, practice of the present invention will result acopolymers with substantially more uniform properties. In other words,the synthesis of even known triblock copolymers such as SBS or MBM mayresult in “novel” polymers from the virtual elimination of 1,2 PBDstructures in the PDB portion of the resulting product.

[0098] For the purposes of clarity, the specific details of theinvention will be illustrated with reference to especially preferredembodiments. However, it should be appreciated that these embodimentsand the appended experimental protocols are for purposes of illustrationonly and are not intended to limit the scope of the present invention.

[0099] Synthesis and Study of Allyl Chloride End-Capped TelechelicPoly(butadiene)

[0100] As shown by Scheme 6, the polymerization of COD in the presenceof the commercially available CTA 1,4-dichloro-cis-2-butene 1 resultedin bis(allyl chloride) functionalized telechelic PBD 2.

[0101] The ring-opening metathesis polymerization were performed in neatCOD and were initiated with ruthenium catalyst 3. An initial study ofthe impact of the COD/CTA ratio, reaction time, and temperature on thepolymer yield, molecular weight, and polydispersity is summarized inTable 1. Table 1 lists the results of optimization studies for the ROMPof COD in the presence of bis(allyl chloride) CTA 1. TABLE 1 COD/CTATemp Yield M_(n) (mol) (° C.) Time (h) (%) X_(n) (GPC) PDI % cis  5/1 2524 75 21 2700 1.59 66  5/1 25 48 77 20 2400 1.58 66  5/1 40 24 73 202600 1.61 66  50/1 25 24 83 90 9400 1.91 63 100/1 25 24 90 145 157002.19 63

[0102] The values for X_(n) were determined by ¹H NMR assumingF_(n)=2.0. The M_(n)(GPC) was determined relative to PS standards inTHF. The % cis refers to percent cis-olefin geometry found in the PBD,as determined by ¹H-NMR. Under otherwise identical conditions, reactionsat 25° C. gave polymers that showed no significant difference from thoseobtained at 40° C. In addition, little difference was observed when thereaction time was increased from 24 to 48 hours. The experimental numberaveraged molecular weights (M_(n,gpc)) of the isolated telechelicpolymers were determined by gel permeation chromatography (“GPC”) andare reported relative to polystyrene standards. While the PDIs of all ofthe isolated polymers were less than or about 2.0, higher monomer to CTAratios resulted in more polydisperse samples. This is most likely due toan increased viscosity of the reaction mixture, which is expected toslow or prevent monomer from reacting with growing polymer chains. Itmay be possible to employ a co-solvent to help alleviate this problem.

[0103] Notably, a “perfect” 1,4-PBD microstructure was found in thepolymer backbone by ¹H NMR. This is highly ideal as these types oflinkages exhibit optimal elastomeric properties. In addition, the PBDcore exhibited about a 66% cis-olefin geometry. Both ¹H and ¹³C NMRsupport a F_(n) near 2.0, in accordance with previous results obtainedby ROMP using symmetrically disubstituted olefin CTAs.

[0104] Synthesis of SBS Triblock Copolymers via ATRP of TelechelicPoly(butadiene) Macroinitiators

[0105] As illustrated by Scheme 7, telechelic PBD 2 with a M_(n)=2400was used to initiate the heterogeneous ATRP of styrene in the presenceof CuBr/bipy (1/3 molar ratio) at 130° C. under inert atmosphere to formSBS triblock copolymers.

[0106] Monomer conversion was monitored by gas chromatography (“GC”)using diphenyl ether as the internal standard. After seven hours, thereactions were cooled to room temperature, diluted with tetrahydrofuran(“THF”) and then poured into an excess of methanol precipitating a whitesolid. Occasionally, the isolated polymer was contaminated with a greenresidue (Cu^(II) salts) which could easily be removed by flash columnchromatography using alumina as the solid phase. TABLE 2 [Sty]_(o)/Entry [Init]_(o) M_(n, theo) M_(n, gpc) M_(n, nmr) PDI % Conv Yield 1 20 4162  4800  4300 1.48 88 75 2 40  6496  7300  6900 1.45 99 99 3 8010188 10100 12300 1.45 93 93 4 120 14929 13800 15900 1.52 97 89 5 18020929 18900 23700 1.74 99 99

[0107] Table 2 summarizes the polymerization results for a variety ofmonomer/initiator ratios. In particular, Table 2 provides data for thesynthesis of SBS triblock copolymers via ATRP of styrene using 2 as amacroinitiator. The general conditions for the reaction include: for theinitiator/CuBr/bipy is 112/6 at 130° C. for 7 hours in Ph₂O solvent andN₂ atmosphere. The telechelic PBD MW is 2400 and PDI is 1.59. Theconcentration of the initiator is 50 mM. The M_(n,theo) was calculatedbased on monomer conversation and assumes F_(n)=2.0. The M_(n,gpc) wasdetermined relative to PS standards in THF. The M_(n,nmr) was determinedby ¹H NMR using a “relative” end-group analysis procedure. The % Convwas determined by GC and the yield was the isolated yield. For entry 5,the reaction was performed in bulk styrene. Good agreement betweenexperimental and theoretical molecular weights (vide infra) indicatethat the telechelic PBDs are efficient ATRP initiators, and that thepolymerizations are well controlled. Only polymerizations performed inbulk styrene gave a PDI above average (˜1.4), presumably due to kineticeffects from the gel-like reaction.

[0108] The tandem ROMP-ATRP approach was also used to prepare SBStriblock copolymers with various sizes of the central PBD block. Theresults are summarized in Table 3. TABLE 3 [Init]_(o) PBD % Entry Time(h) (mM) MW M_(n, theo) M_(n, gpc) M_(n, nmr) PDI Conv. 1 7 50  240010188 10100 12300 1.45 93 2 9 30  9900 16267 13000 16900 1.94 60 3 16 1515800 20850 18900 20400 2.87 54

[0109] The general conditions for the reaction include: for theinitiator/CuBr/bipy is 1/2/6 at 130° C. in Ph₂O solvent and N₂atmosphere. The ratio of [styrene]_(o)/[init]_(o) is 80. The M_(n,theo)was calculated based on monomer conversation and assumes F_(n)=2.0. TheM_(n,gpc) was determined relative to PS standards in THF. The M_(n,nmr)was determined by ¹H NMR using a “relative” end-group analysisprocedure. The % Conv was determined by GC. Polydispersity of the SBStriblock copolymers increased with macroinitiator length and may be theresult of using telechelic PBD with a F_(n) less than 2.0. Grubbs andHillmyer have shown that when synthesizing higher molecular weighttelechelic PBDs, the monomer to catalyst ratio must be accordinglyincreased to reduce the catalysts negative contribution to F_(n). As aresult, all telechelic PBDs in this study were synthesized with amonomer to catalyst ratio of 2000.

[0110] The high molecular weight nature of the PBD prevented an accuratedetermination of the F_(n) of entries 2 and 3 (Table 3) by ¹H NMR, buttheir theoretical F_(n)'s were calculated to be 1.95 and 1.90,respectively. As such, between 5 and 10% of the polymer chains may bediblocks. By way of comparison, entry 1 (Table 3) has a theoreticalF_(n) of 1.99 and thus less than 1% of the polymer chains are diblocks.Longer reaction times may be another explanation for the relativelylarge PDI of the SBS triblocks. Since the rate of reaction was reducedby the relatively larger amounts of solvent required to dissolve thehigher molecular PBD, more time would be allocated for side reactions(such as elimination or termination) to occur. The M_(n,gpc) valuesagree with the theoretical molecular weights (“M_(n,theo)”) which werecalculated based on monomer conversion and the assumption that eachmacroinitiator chain contained two allyl chloride end groups. GPCmeasurements also indicated that the molecular weight distributions wereunimodal and no signal attributed to the starting macroinitiators; couldbe detected. Typical GPC chromatograms of the starting telechelic PBD 2and SBS triblock copolymers are illustrated in FIG. 2. FIG. 2 shows atypical GPC trace of telechelic PBD 2 and SBS triblock copolymerprepared via ATRP of styrene initiated with PBD 2. In FIG. 2, the solidline shows the chromatogram for an SBS triblock copolymer having anM_(n) of 10300 and an PDI of 1.45 and the dotted line show thechromatogram for telechelic polybutadiene 2 having an M_(n) of 2900 andPDI of 1.63.

[0111] The SBS triblock copolymers were also examined using ¹H NMRspectroscopy. Comparison of the ¹H NMR spectra of the telechelicmacroinitiator (bottom) and the SBS triblock copolymers synthesized by atandem ROMP-ATRP approach (top) are illustrated in FIG. 3. Examinationof the PBD backbone of the MBM triblocks revealed no change in thecis-olefin content relative to the telechelic PBD, and only 1,4-PBDlinkages were found. Two signals at 4.03 and 4.09 ppm, attributable tocis and trans allyl chloride end-groups of the PBD 2, respectively, wereused to determine molecular weight via end-group analysis. These signalsvanish upon the ATRP of styrene. New signals from the terminal benzylchloride groups form at 4.55 ppm, but are too small to accuratelydetermine the molecular weight of the SBS. Assuming that all of theallyl chloride end groups initiate, as seen in FIG. 3, integration ofthe proton resonances from the aryl groups of PS relative to theolefinic signals provides information on the amount of styreneincorporated into the triblock copolymer. Excellent agreement betweenM_(n,theo) and the M_(n,nmr) is obtained by this method.

[0112] Since GPC or ¹H NMR does not allow the discrimination betweendiblock and triblock copolymers of identical molecular weight, a methodbased on the cleavage of the central PBD block was used to determineblock arrangement. Thus, PBD degradation of a SBS triblock copolymer(entry 3, Table 2, MW=12300) should return PS with a molecular weight of4950. However, a SB diblock structure must be assumed if the molecularweight of the isolated PS is two-fold higher than expected. Degradationof the PBD core of SBS with OsO₄/H₂O₂ gave PS with M_(n,gpc)=4900(PDI=1.23). No PBD was observed in the ¹H NMR spectra indicating thatthe degradation was complete. Thus, this result provides direct evidencethat the arrangement of SBS polymers synthesized using the tandemROMP/ATRP approach were indeed triblock in nature.

[0113] Mixed Halide Catalyst Systems

[0114] Matyjaszewski and coworkers have recently reported that mixedhalide systems (where the initiator and organometallic complex containdifferent halides) can provide better agreement between M_(n,theo) andexperimental molecular weights and lower PDIs. The basis for theincreased control is thermodynamic. ATRP is an equilibrium process andgoverned by relative copper^(II) halide and carbon halide bond energies.Since a copper^(II) bromide bond is weaker than a copper^(II) chloridebond, lower PDIs should be observed when employing CuBr as the catalystdue to faster deactivation rates.

[0115] To determine whether a mixed halide system provides lower PDIs inthe above experiments, several SBS triblock copolymers were synthesizedusing both CuCl and CuBr. Table 4 shows a comparison in polymerizationresults between mixed halide and single halide systems. TABLE 4 Metal[Sty]_(o)/ Entry System [Init]_(o) M_(n, theo) M_(n, sec) PDI % Conv 1CuCl 80 10459 10300 1.45 96 2 CuBr 80 10188 10100 1.45 93 3 CuCl 20 4283  4900 1.51 90 4 CuBr 20  4162  4800 1.48 88

[0116] The general conditions for the reaction include: for theinitiator/CuBr/bipy is 1/2/6 at 130° C. for 7 hours in Ph₂O solvent andN₂ atmosphere. The telechelic PBD MW is 2400 and PDI is 1.59. Theconcentration of the initiator is 50 mM. The M_(n,theo) was calculatedbased on monomer conversation and assumes F_(n)=2.0. The M_(n,sec) wasdetermined relative to PS standards in THF. The % Conv was determined byGC. The reactions employing CuBr polymerize at a slighter slower rate(vide infra) which is a manifestation of an increased deactivation rate.However, no significant difference in polydispersity between the twometal systems was found. Thus, these results suggest that mixed halidesystems have no substantial advantage over analogous single halidesystems in these reactions. In other words, ATRP of styrene using ananalogous bromide based macroinitiator with CuCl as the catalyst mayprovide an alternative route to controlling the polymerization throughhalide exchange.

[0117] Kinetics of the ATRP of Styrene

[0118] For comparison, the rates of the CuBr and CuCl catalyzed ATRP ofstyrene using telechelic PBD macroinitiator 2 were monitored using gaschromatography and GPC. To avoid any fractionation of the polymersamples during isolation, which would artificially narrow the PDIs,aliquots from the polymerization were diluted with THF eluted through ashort column of alumina to remove any metal salts and then injecteddirectly into the GPC.

[0119]FIG. 4 presents kinetic data for the polymerization of styrenefrom a telechelic PBD macroinitiator (MW=2400) in the presence of theCuCl bipy catalyst system. In particular, FIG. 4 shows the kinetics ofATRP of styrene at 130° C., initiated with 2, using CuBr and CuClcatalysts. The concentration of the initiator was 50 mM, [CuX]_(o) was100 mM, [bipy]_(o) was 300 mM, [styrene]_(o) was 4 M. The reactionoccurred in the presence of Ph₂O as a solvent. The straightsemilogarithmic plot of In ([M]₀/[M]) vs. time gives a pseudo-firstorder rate constant of 7.3×10⁻³ M⁻¹ min⁻¹ and indicates that theconcentration of growing radicals is constant. The semilogarithmic plotof In ([M]₀/[M]) vs. time for CuBr has a slight curvature at lowconversion which may result from some halide exchange effects.Nevertheless, a pseudo-first order rate constant of 4.4×10⁻³ M⁻¹ min⁻¹was derived which agrees with Matyjaszewski's result of 4.5×10⁻³ M⁻¹min⁻¹ for the ATRP of styrene using allyl chloride as the initiator. Theslower polymerization rate for the CuBr system relative to the CuClsystem supports the faster deactivation rate concluded above.

[0120] In addition, M_(n,gpc) linearly increases with monomer conversionfor both the CuCl and CuBr metal systems and closely matches M_(n,theo).As shown in FIG. 5, the molecular weight and PDI dependence on monomerconversion for ATRP of styrene initiated with 2 using CuBr and CuClcatalysts. The concentration of the initiator was 50 mM, [CuX]o was 100mM, [bipy]_(o) was 300 mM, [styrene]_(o), was 4 M. The reaction occurredin the presence of Ph₂O as a solvent. The slight discrepancies betweenthe experimental and theoretical data may be related to differences inhydrodynamic volume between the SBS triblocks and the PS standards usedto calibrate the GPC. This result provides additional evidence thattelechelic PBD 2 is an efficient initiator and the number of activechains remains constant during the polymerization.

[0121] Controlling Polydispersity: Effects of Catalyst Solubility andTemperature

[0122] Matyjaszewski and coworkers have shown that the polydispersity ofthe polymers obtained using ATRP is strongly affected by the solubilityof the mediating metal. Using ligands with a long or branched alkylside-chains were found to completely dissolve the metal complexresulting in polymers with a remarkably low PDI (1.05). To determinewhether a soluble copper catalyst would reduce the PDI of resultant SBStriblock copolymers, a known bipyridine derivative,4-4′-di-n-heptyl-2,2′-bipyridine (“dHbipy”) 4, was employed.

[0123] As expected, copper complexes containing ligand 4 were moresoluble than complexes containing bipy. ATRP of styrene using ligand 4under conditions identical to entry 3 (Table 2) produces a SBS triblockwith a relatively lower PDI (1.25 vs. 1.45, Table 5). This low PDI iscompetitive with SBS produced anionically.

[0124] Table 5 shows the effects of ligand temperature on SBSpolydisperity: TABLE 5 Entry/ Temp [Sty]_(o)/ Ligand (° C.) [Init]_(o)M_(n, theo) M_(n, gpc) PDI % Conv. 1/bipy 130 80 10188 10100 1.45 932/dHbipy 130 80  9607 10000 1.25 92 (4) 3/bipy 110 80  8356  6800 1.3671 4/bipy 130 80  8302  7000 1.31 70

[0125] The general conditions for the reaction include: for theinitiator/CuBr/ligand is 1/2/6 for 7 hours in Ph₂O solvent and N₂atmosphere. The telechelic PBD MW is 2400 and PDI is 1.59. Theconcentration of the initiator is 50 mM. The M_(n,theo) was calculatedbased on monomer conversation and assumes F_(n)=2.0. The M_(n,gpc) wasdetermined relative to PS standards in THF. The % Conv was determined byGC. Entry 1 was obtained from data from Table 2, entry 3.

[0126] Employing lower reaction temperatures can minimize termination orside reactions, such as halide elimination. The ATRP of styrene withmacroinitiator 2 at 110° C. lowered the PDI from 1.45 to 1.36. However,the reaction was significantly slower, achieving only 71% conversionafter seven hours. For comparison, an analogous polymerization at 130°C. reaches a similar conversion after only two hours and gives a polymerwith a PDI=1.3 1. Thus, there appears to be no advantage in runningthese polymerizations at lower temperatures.

[0127] One Pot Synthesis of SBS Triblock Copolymers

[0128] The ability to extend the tandem ROMP-ATRP approach to SBStriblock copolymers into a one-pot process was demonstrated by thefollowing experiment. A telechelic PBD was prepared as described above(entry 3, Table 2) in a Schlenk flask and assumed to produce polymer in75% yield with a molecular weight of 2400 after 24 hours. Afterterminating the polymerization with ethyl vinyl ether, the polymer wasplaced under dynamic high vacuum to remove any residual monomer, CTA,terminating agent, and low molecular weight cyclic olefins. The flaskwas then placed under inert atmosphere and charged with appropriateamounts of CuBr, bipy, styrene, and diphenyl ether. After 7 hours at130° C., SBS triblock copolymer with a MW and PDI similar to SBSproduced via the two step method discussed above was obtained. Table 6provides data for a one pot synthesis of SBS triblock copolymers. Onepot or two pot refers to the total number of reaction vessels employedduring the synthesis. TABLE 6 Entry Conditions M_(n, theo) M_(n, sec)PDI % Conv 1 2-Pot, CuBr 10188 10100 1.45 93 2 1-Pot, CuBr  9795 105001.40 92 3 1-Pot, Cu^(o) 12000 11400 1.66 60 4 1-Pot, Cu^(o)  8254  80001.63 73

[0129] The general conditions for the reaction include: for theinitiator/Cu° or CuBr/bipy is 1/2/6 at 130° C. for 7 hours in Ph₂Osolvent and N₂ atmosphere. The telechelic PBD MW is 2400 and PDI is 1.59(which is assumed for entries 2-4). The concentration of the initiatoris approximately 50 mM. The M_(n,theo) was calculated based on monomerconversation and assumes F_(n)=2.0. The M_(n,sec) was determinedrelative to PS standards in THF. The % Conv was determined by GC. Entry1 was obtained from data from Table 2, entry 3. Data for Entries 2 and 3was obtained under conditions of high vacuum applied after PBDpolymerization was terminated to remove impurities. No vacuum wasapplied at any point during the synthesis for entry 4. Radicalpolymerizations generally must be carried out in oxygen-freeenvironments to prevent reaction of oxygen with organic free radicalsand/or catalyst. However, Matyjaszewski has recently shown that ATRP canoccur in a closed system under an atmosphere of air when Cu⁰ (combinedwith small amounts of Cu^(II)) is used in lieu of Cu^(I) halide salts.As shown by Scheme 8, copper(0) powder recycles Cu^(II) to the activeCu^(I) catalyst through a dynamic equilibrium that includes theeffective removal of adventitious oxygen in the solution and in theheadspace above the solution.

[0130] Remarkably, this process was also found to deactivate radicalscavengers such as 4-tert-butylcatechol (“BHT”) and hydroquinonemonomethyl ether (“MEHQ”). This has allowed the synthesis ofwell-defined polymers via ATRP using unpurified monomers and solventsand circumvents the need for sophisticated techniques and equipmentnecessary to obtain inert atmospheres.

[0131] The synthesis of SBS triblock copolymers via a simplified one-potprocedure was performed as follows. A telechelic PBD with an assumedmolecular weight of 2400 and yield of 75% was prepared as above. Afterterminating with ethyl vinyl ether, the flask was charged withappropriate amounts of phenyl ether, styrene, bipyr, copper powder, andCuBr₂. All reagents were used as received and no vacuum was appliedafter termination. The flask was capped and placed in an oil bath at130° C. for 7 hours. As shown in Table 6, monomer conversion is lowerthan the analogous two-pot synthesis (Table 2, entry 3), presumably dueto relatively more dilute conditions. While good agreement between thetheoretical and the experimental MW was observed, the PDI is relativelylarge. This may reflect copper deactivation through coordination withethyl vinyl ether. However, no significant difference from a controlexperiment where the residual ethyl vinyl ether was removed beforeadding the reagents necessary for the ATRP of styrene was observed(Table 6).

[0132] Attempted Synthesis of MBM Triblock Copolymers via ATRP of MMAInitiated with 2

[0133] Recently, significant attention has focused on the synthesis ofwell-defined MBM triblock copolymers. It has been concluded that onlyMBM with a low 1,4-PBD microstructure content and dismal elastomericproperties can be prepared anionically. Since the SBS triblocks preparedin this study were shown to have entirely 1,4-PBD microstructure, a newroute to MBM triblock copolymers via a tandem ROMP-ATRP approach wasfurther explored.

[0134] The preparation of MBM using allyl chloride terminated telechelicPBDs 2 as macroinitiators for the ATRP of MMA was attempted under amyriad of conditions, including variations on time, temperature, andcatalyst concentration.

[0135] Scheme 9 depicts the attempted synthetic route.

[0136] As illustrated by FIG. 6, bimodal distributions were consistentlyfound in the GPC traces. FIG. 6 shows the retention volume of MBMtriblock copolymers obtained by ATRP of MMA using 2. The low molecularweight peak is in the range of unreacted macroinitiator and suggests thehigh molecular weight peak corresponds to a mixture of triblock anddiblock copolymers. The bimodality is presumably due an initiation raterelatively slow to propagation. This is supported by a decreasing lowmolecular weight peak area with monomer conversion and the observationof residual allyl chloride resonances in the ¹H NMR spectra of theisolated polymers.

[0137] Further evidence of slow initiation was provided through akinetics study of the ATRP of MMA using macroinitiator 2. FIG. 7 showsthe kinetics data of the ATRP of MMA initiated with 2 using CuCl andCuBr catalysts. As illustrated, FIG. 7 presents the polymerizationkinetic data using a telechelic PBD (MW=2700) in the presence ofCuCl/bipy (1/3) at 130° C. The semilogarithmic plot of In ([M]₀/[M]) vs.time indicates that the concentration of radicals is nonlinear andprevented derivation of a pseudo-first order rate constant. Theexperimental molecular weights increased with monomer conversion, butthe molecular weights were higher than theoretical predictions based onquantitative initiation.

[0138] Analogous results using CuBr/bipy as the catalyst were alsoobserved. Recently, two nickel-based ATRP catalysts, NiBr₂(PPh₃)₂ andNiBr₂(PnBu₃)₂, were reported to polymerize MMA at a much slower ratecompared to copper based systems. However, nickel catalyzed ATRP of MMAusing 2 showed no improvement and bimodal distributions were stillobserved.

[0139] Synthesis and Study of 2-Bromo Propionate Capped TelechelicPoly(butadiene)

[0140] Both 2-bromo isobutyrates and 2-bromo propionates have been shownto be efficient ATRP initiators of MMA. Thus, their potential as CTAs inthe ROMP of COD was investigated. As illustrated by Scheme 10, simpleesterification of commercially available cis-2-butene-1,4-diol with anexcess of the appropriate acid bromide gave bis(2-bromo isobutyrate) 6and bis(2-bromo propionate) 8.

[0141] Due to purification difficulties with 6, only 8 was used forfurther study. The ROMP of COD in the presence of the CTA 8 resulted inbis(2-bromo propionate) functionalized telechelic PBD 9 as shown inScheme 11.

[0142] The polymerizations were run in a similar manner as 2 and theresults for a variety of conditions investigated are summarized in Table7. Table 7 lists the results of the optimization studies for the ROMP ofCOD in the presence of bis(2-bromopropionyl) CTA 8. TABLE 7 COD/CTA TempYield M_(n) (mol) (° C.) Time (h) (%) X_(n) (GPC) PDI % cis  5/1 25 2464  23  4900 1.49 64  5/1 25 48 58  24  4700 1.52 61  5/1 40 24 59  28 5000 1.50 65  10/1 25 24 75  30  5300 1.62 66  50/1 25 24 87 120 167002.08 63 100/1 25 24 85 128 24400 2.31 60

[0143] As shown in Table 7, the X_(n) was determined by ¹H NMR assumingthat F_(n)=2.0.

[0144] The M_(n) (GPC) was determined relative to PMMA standards in THF.% cis refers to percent cis-olefin found in the PBD, as determined by ¹HNMR. Analogous to the PBD 2, long reaction times and elevatedtemperatures had little or no effect on the polymerization results. Themolecular weights determined by ¹H NMR using end group analysis weresignificantly lower than those obtained by GPC presumably due to thelarge differences in hydrodynamic volume between PBD and the PMMAstandards used for calibration. The PDI of the isolated polymers werebetween 1.5 and 2.3. ¹H and ¹³C NMR indicated the presence of only1,4-PBD linkages in the polymer backbone and supported a F_(n) near 2.0.In addition, the PBD exhibited ca. 66% cis-olefin geometry.

[0145] Synthesis of MBM Triblock Copolymers via ATRP of TelechelicMacroinitiators

[0146] As illustrated by Scheme 12, telechelic PBD 9 was used as amacroinitiator for the heterogeneous ATRP of MMA to produce MB Mtriblock copolymers.

[0147] The polymerizations were run under similar conditions as for thesynthesis of SBS. After 2.5 hours at 100° C., the polymerizations wereterminated by pouring the reactions into an excess of methanol causingthe immediate precipitation of a white solid. Table 8 summarizes thepolymerization results for a variety of monomer/initiator ratios. Inparticular, Table 8 provides data obtained during the synthesis of MBMtriblock copolymers via ATRP of MMA initiated with telechelicpoly(butadiene). TABLE 8 [Sty]_(o)/ Entry [Init]_(o) M_(n, theo)M_(n, gpc) M_(n, nmr) PDI % Conv. Yield 1 20  4431  9400  4700 1.58 8677 2 80 10548 18100 11500 1.54 99 90 3 180 20561 28300 23900 1.59 99 884 360 38743 49600 41700 1.68 99 99

[0148] The general conditions for the reaction include: for theinitiator/CuCl/bipy is 1/2/6 at 100° C. for 2.5 hours in Ph₂O solventand N₂ atmosphere. The telechelic PBD MW is 2700 and PDI is 1.49. Theconcentration of the initiator is 25 mM. The M_(n,theo) was calculatedbased on monomer conversation and assumes F_(n)=2.0. The M_(n,gpc) wasdetermined relative to PMMA standards in THF. The M_(n,nmr) wasdetermined by ¹H NMR using a “relative” end-group analysis procedure.The % Conv was determined by GC and the yield was the isolated yield.For entry 4, the reaction was performed in bulk MMA. GPC traces showedthat the triblock copolymer MW distributions are unimodal and low (ca.1.6). In addition, agreement between M_(n,gpc) and the theoreticalM_(n,theo), improved with length of the PMMA segments. Typical GPCchromatograms of the starting telechelic PBD and MBM triblock copolymerare illustrated in FIG. 8. In particular, FIG. 8 shows the typical SECtraces of PBD 9 and MBM synthesized by ATRP of MMA initiated with 9. Thesolid line represents an MBM triblock copolymer having an M_(n) of 10300and a PDI of 1.54. The dotted line depicts a telechelic PBD 9 having anM_(n) of 2700 and a PDI of 1.63. The ¹H NMR spectrum of the PBD 9 showstwo signals at 4.60 and 4.71 ppm attributable to cis and trans allylicester end-groups, respectively, and were used to determine molecularweights via end-group analysis, assuming F_(n)=2.0. FIG. 9 illustrates acomparison between the ¹H NMR spectra of telechelic PBD 9 (top) and MBMtriblock copolymer synthesized via tandem ROMP-ATRP (bottom). While the¹H NMR spectrum of the MBM triblocks reveals that the allylic estersignals have completely vanished, the new bromo-methacrylate end-groupresonances (4.23 ppm) were barely observable. However, molecular weightdata could still be obtained using the “relative” end group approachdiscussed above. No change in the PBD microstructure in the MBM triblockcopolymers was found.

[0149] A variety of other catalyst systems were explored in thesynthesis of MBM (Table 9). The CuBr/bipy system, which was effective inthe synthesis of SBS, was found to give MBM with bimodal distributionsin the GPC spectrum. This may a consequence of halide exchange effectsas alkyl bromide initiators combined with CuBr metal systems give fastinitiation and fast propagation rates due to the relatively weak carbonbromide bond. The success of using R—Br/CuCl is attributable to therelatively strong carbon-chloride bond. Due the equilibrium nature ofATRP, shortly after initiation, nearly all of the active polymer chainsare deactivated with chloride atoms. The stronger carbon-chloride bonddrastically slows propagation allowing a controlled polymerization tooccur. In addition, the results of employing two nickel based ATRPcatalyst systems, NiBr₂(PPh₃)₂ and NiBr2(PnBu₃)₂, are summarized inTable 9. All catalyst systems except CuCl/bipy resulted in eitherbimodal or polydisperse distributions. Table 9 shows the results of thesynthesis of MBM triblock copolymers using a variety of catalysts. TABLE9 Entry Catalyst M_(n, theo) M_(n, gpc) PDI % Conv. 1 CuCl/Bipy 1054818300 1.54 99 2 CuBr/Bipy 10356 37500 96 3 NiBr₂(Pη-Bu₃)₂ 11300 232003.34 99 4 NiBr₂(PPh₃)₂  9873 23300 3.27 90

[0150] The general conditions common to all polymerizations include thetelechelic PBD MW is 2700, the PDI is 1.6 and the [MMA]_(o)/[Init]_(o),is 80. For the copper based systems, the initiator/CuCl/bipy is 1/2/6 at100° C. for 2.5 hours in Ph₂O solvent and N₂ atmosphere. Theconcentration of the initiator is 25 mM. For nickel based systems, theinitiator/Al(OiPr)₃ is 1/4 at 100° C. for 18 hours in toluene solventand N₂ atmosphere. The concentration of the initiator is 20 mM. TheM_(n,theo) was calculated based on monomer conversation and assumesF_(n)=2.0. The M_(n,gpc) was determined relative to PMMA standards inTHF. The % Conv was determined by GC. For entry 2, the M_(n,gpc) entryof 37500 reflects the MP of high MW peak. There is no PDI entry forentry 2 due to bimodal distribution. In addition, for entry 3, theNi/Initiator is 8 and for entry 4, the Ni/initiator is 1.

[0151] Kinetics of the ATRP of Methyl Methacrylate

[0152] The kinetics of the ATRP of MMA using telechelic PBDmacroinitiators were studied with the CuCl/bipy catalyst system. FIG. 10shows the kinetics data of the ATRP of MMA initiated by 9 catalyzed byCuCl, at 100° C. in Ph₂O. The concentration of the initiator was 50 mM,[CuCl]_(o) was 100 mM, [bipy]_(o), was 300 mM, [MMA] _(o) was 4 M. Thelinear semilogarithmic plot of In ([M]₀/[M]) vs. time indicates aconstant concentration of growing radicals and a pseudo-first order rateconstant of 3.5×10⁻²M⁻¹ min⁻¹ was derived. FIG. 11 shows the molecularweight and PDI dependence on monomer conversion for ATRP of MMAinitiated by 9 using CuCl catalyst in Ph₂O. The concentration of theinitiator was 50 mM, [CuX]_(o) was 100 mM, [bipy]_(o) was 300 mM,[MMA]_(o) was 4 M. The experimental molecular weight determined by GPClinearly increases with monomer conversion for the CuCl metal system,but is larger than the M_(n,theo) (FIG. 11). Polydispersity remained low(<1.6) throughout the polymerization. These results provide solidevidence that the telechelic PBD macroinitiator 9 is efficient and thenumber of active chains remains constant during the polymerization.

[0153] In summary, two CTAs functionalized with allyl chloride and2-bromopropionyl ester groups were synthesized and successfully employedin the ROMP of COD to prepare telechelic PBDs. The impact of reactiontime, temperature, and the monomer to CTA ratio on the polymerizationswere investigated. Resultant polymers were found to contain only 1,4-PBDmicrostructure with predominately cis-olefin geometry.

[0154] The bis(allyl chloride) telechelic PBD was successfully employedas a macroinitiator for the ATRP of styrene using CuCl/bipy andCuBr/bipy catalyst systems. Well-defined SBS triblock copolymers withvarying PBD and PS block lengths, predetermined molecular weights, andlow polydispersity were obtained. Degradation of the PBD core andexamination of the residual PS chains confirmed a triblock structure.Polydispersity could be effectively reduced under homogenous ATRPconditions through utilization of a more soluble bipyridine derivative.Examination of the kinetics of the ATRP of styrene using the bis(allylchloride) macroinitiator revealed pseudo first order behavior.

[0155] The bis(2-bromopropionyl ester) telechelic PBD was found to be anefficient initiator for the ATRP of MMA. Of a variety of metal catalystsemployed, only CuCl/bipy was found to give well-defined MBM triblockcopolymer with predictable molecular weights and low polydispersity.Polymerization kinetics were investigated and found to exhibit firstorder behavior.

[0156] A variety of well-defined SBS and MBM triblock copolymers havebeen synthesized via a tandem ROMP-ATRP approach. Both polymers containvery low levels of diblock contamination and the PBD backbone exhibits aperfect 1,4-microstructure. Since anionic methods of producing SBS andMBM triblocks introduce some degree of 1,2-PBD microstructure, thepolymers prepared in this study may exhibit novel elastomericproperties. In addition, this approach is a milder and much easiermethod of synthesizing SBS and MBM triblocks than the anionic methodscurrently employed.

Experimental Section

[0157] General Considerations.

[0158] All air sensitive manipulations were performed in anitrogen-filled dry box or by using standard Schlenk techniques under anatmosphere of argon. Argon was purified by passage through columns ofBASF R3-11 catalyst (Chemalog) and 4 A molecular sieves (Linde). NMRspectra were recorded using a GE QE-300 Plus (300.1 MHz ¹H; 75.49 MHz¹³C) instrument in the indicated solvent. Chemical shift were recordedin parts per million (δ) and splitting patterns are designated as s,singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br, broad.Coupling constants, J, are reported in Hertz (Hz). Chloroform-d (7.26ppm for ¹H, 77.0 ppm for ¹³C) was used as an internal standard. Gaschromatography (“GC”) was performed on a HP-5890 Series II gaschromatographer equipped with a 15 m×0.53 mm×0.5 μm J & W Scientific,Inc. DB-I dimethylpolysiloxane column and fitted with a flame ionizationdetector using helium as a carrier gas with a flow rate of 30 mL/min.Gel permeation chromatographs were obtained on a HPLC system using anAltex model 426 pump, a Rheodyne model 7125 injector with a 100 μLinjection loop, two American Polymer Standards 10 micron mixed bedcolumns, and a Viscotek model 200 differential refractometer/viscometerusing a 1.0 mL/min flow rate. Molecular weight and polydispersities werereported versus monodispersed poly(styrene) (“PS”) or poly(methylmethacrylate) (“PMMA”) standards. Flash chromatography was carried outwith Silica Gel 60 (230-400 mesh) from EM Science or basic alumina gelfrom Fluka Chemical Company. Analytical thin layer chromatography(“TLC”) was performed on KIESELGEL F-254 precoated silica gel or neutralalumina plates. Visualization was accomplished with UV light and ananisaldehyde stain.

[0159] Materials.

[0160] Tetrahydrofuran (“THF”), toluene, and dichloromethane were driedand degassed by passage through solvent purification columns containingactivated alumina. Diphenyl ether was degassed by three successivefreeze-pump-thaw cycles. All other solvents were reagent grade and usedwithout further purification. Cyclooctadiene (99+%, packed undernitrogen) was purchased from Aldrich Chemical Company was used asreceived. Styrene and methyl methacrylate were purified by passagethrough inhibitor removal columns (Aldrich), and then degassed and thenstored at −40° C. 1,4-dichloro-2-butene (1) was purified by passagethrough an alumina column and then degassed. All other reagents werepurchased from Aldrich Chemical Company and used without furtherpurification.

[0161] Cis-2-butene-1,4-diol bis(2-bromo)isobutyrate (6).

[0162] cis-2-Butene-1,4-diol (1.50 mL, 18.2 mmol, 1.0 equiv) wassuspended in CH₂Cl₂ (100 mL) in a 300 mL round bottom flask under argon.The flask was then charged with 2-bromoisobutyryl bromide (4.50 mL, 36.4mmol, 2.0 equiv) via syringe over 10 minutes during which time thereaction mixture turned yellow and slightly cloudy. Addition oftriethylamine (5.05 g, 36.2 mmol, 2.0 equiv) via syringe caused theimmediate formation of white precipitate which dissolved after one hourat ambient temperature. The resulting yellowish solution was poured intoa 1 L separatory funnel and then washed with deionized water (4×50 mL)and brine (1×100 mL). The organic layer was collected and dried overMgSO₄. After filtering away Mg solids, the solution was concentrated invacuo to give a yellow oil (5.59 g, 80% yield). The compound was foundto be unstable on silica gel or alumina preventing purification by flashcolumn chromatography. ¹H NMR (CDCl₃) δ 5.81 (t, J=4.5 Hz, 2H), 4.79 (d,J=4.8 Hz, 4H), 1.91 (s, 12H).

[0163] Cis-2-butene-1,4-diol bis(2-bromo)propionate (8).

[0164] A 500 mL round bottom flask under argon was charged with CH₂Cl₂(150 mL), cis-2-butene-1,4-diol (2.0 mL, 24.3 mmol, 1.0 equiv), andtriethylamine (10.5 mL, 75.3 mmol, 3.1 equiv). The dropwise addition of2-bromopropionyl bromide (8.0 mL, 76.4 mmol, 3.1 equiv) at ambienttemperature caused the reaction mixture to turn orange in color followeda slight increase in temperature. The reaction was left to stir atambient temperature under argon for 15 hours. The reaction was thenpoured into a 1 L separatory funnel and washed with deionized watersaturated with sodium bicarbonate (3×100 mL), deionized water (3×100 mL)and 100 mL of brine. The organic layer was collected and dried overMgSO₄. After filtering away Mg solids, the solution was concentrated invacuo to give a yellow oil. The product was purified by flash columnchromatography (silica gel, 9:1 hexanes/ethyl acetate (v/v), R_(f)=0.10)to give 5.3 8 g (62%) or pure product as a viscous oil. ¹H NMR (CDCl₃) δ5.81 (t, J=4.5 Hz, 2H), 4.79 (d, J=4.8 Hz, 4H), 1.91 (s, 12H).

[0165] General Procedure for Preparing Telechelic Poly(butadienes).

[0166] All manipulations were carried out in a nitrogen filled dry box.A 10 mL vial was charged with appropriate amounts of either1,4-dichloro-2-butene (1) or cis-2-butene-1,4-diolbis(2-bromo)propionate (8), COD, and a stir bar. In a separate vial, thecorrect amount of initiator (3) was weighed out and then combined withthe COD/CTA mixture forming a purple solution. The vial was then capped,removed from the dry box, and let stir for the desired time upon whichan excess of ethyl vinyl ether was pipetted into the vial. The reactionwas then stirred at room temperature for 1 h followed by precipitationinto MeOH. The MeOH was then decanted away and the polymer was washedwith fresh MeOH to remove any remaining COD or CTA. The resultingpolymer was concentrated in vacuo and then characterized by ¹H NMR, ¹³CNMR, and GPC.

[0167] Bis(allyl chloride)-Functionalized Telechelic Poly(butadiene)(2).

[0168] Spectral data for the polymer obtained from a 5:1 COD/I ratio: ¹HNMR (CDCl₃) 8 5.39-5.43 (br, 83H), 4.09 (d, J=6.9 Hz, 1.5H), 4.03 (d,6.8 Hz, 2.5H), 2.08-2.04 (br, 166H); M_(n)=2400, X_(n)=21. GPC (relativeto poly(styrene) standards): M_(n)=2700, M_(w)=4200, PDI=1.59.

[0169] Bis(2-bromopropionate)-Functionalized Telechelic Poly(butadiene)(9).

[0170] Spectral data for the polymer obtained from a 5:1 COD/8 ratio: ¹HNMR (CDCl₃) δ 5.37-5.41 (br, 94H), 4.71 (d, 4 J=6.8 Hz, 1.5H), 4.60 (d,J=6.7 Hz, 2.5H), 4.37 (q, 6.9 Hz, 2H), 2.03-2.05 (br, 188H), 1.82 (d,J=6.7 Hz, 6H); M_(n)=2700, X_(n)=23. GPC (relative to poly(methylmethacrylate) standards): M_(n)=5500, M_(w)=8600, PDI=1.57.

[0171] General Procedure for ATRP of Styrene or Methyl Methacrylate.

[0172] All manipulations were carried out in a nitrogen filled dry box.A 10 mL vial was charged with appropriate amounts of macroinitiator 2 or9, diphenyl ether, and styrene or methyl methacrylate. In a separatevial, correct amounts of CuCl or CuBr and bipyridine were added. Thecontents of both vials were then transferred to a Schlenk flaskpreviously charged with a stir bar, generally giving a brown mixture.The flask was then capped tightly, covered with aluminum foil andremoved from the dry box. After stirring in an oil bath set at anappropriate temperature for the desired amount of time, the flask wascooled to room temperature and poured into a large excess of MeOHcausing the precipitation of a white polymer. The MeOH was decanted awayand the polymer was washed several times with fresh MeOH and then driedunder dynamic high vacuum. The SBS triblock copolymers were occasionallycontaminated with a green residue which could easily be removed bypassage through a short column of alumina (using THF as the eluent). Theresulting polymer was then concentrated in vacuo and then dried underhigh vacuum. The resulting polymer was concentrated in vacuo and thencharacterized by ¹H NMR, ¹³C NMR, and GPC. SBS triblock copolymersrequired the use of CS₂ as the solvent to avoid interference withresidual protons in deuterated solvents. Data was thus acquired withouta solvent lock and generally only one scan was taken to eliminate anyerrors related to differences in relaxation times.

[0173] Poly(styrene)-b-poly(butadiene)-b-poly(styrene) (“SBS”).

[0174] Spectral data for a SBS triblock copolymer obtained from a 80:1styrene/2 ratio: ¹H NMR (CS₂) δ 7.13-6.49 (br, 7.07H), 5.48-5.43 (br,1H), 2.16-2.13 (br, 2.24H), 1.94-1.45 (br, 4.24H); M_(n)=12300, X_(n)(styrene)=95. GPC (relative to PS standards): M_(n)=10300, M_(w)=14900,PDI=1.45.

[0175] Poly(methyl methacrylate)-b-poly(butadiene)-b-poly(methylmethacrylate) (“MBM”).

[0176] Spectral data for a MBM triblock copolymer obtained from a 80:1MMA/9 ratio: ¹H NMR (CDCl₃) δ 5.43-5.37 (br, 1H), 3.60 (br, 2.88H),1.93-1.81 (br, 2H), 1.22-0.84 (br, 2.88H); M_(n)=11500, X_(n) (methylmethacrylate)=95. GPC (relative to PMMA standards): M_(n)=18 100,M_(w)=27900, PDI=1.54.

[0177] Procedure for PBD Degradation.

[0178] A 100 mL round bottom flask was charged with a stir bar, SBStriblock copolymer (500 mg, MW=12300 by ¹H NMR), and o-dichlorobenzene(50 mL). To the solution was added H₂O₂ (30% w/w solution in H₂O, 10 mL)and OsO₄(3.93 mM solution in benzene, 1 mL). The mixture was then placedin an oil bath at 90° C. for 6 h at which point all of the H₂Oevaporated leaving a colorless solution. The reaction was cooled to roomtemperature and poured into excess MeOH precipating a white polymer. TheMeOH was decanted away and the polymer was washed several times withfresh MeOH and then placed under high vacuum to dry giving 228.5 mg ofpolystyrene. GPC (relative to PS standards): M_(n)=4900, M_(w)=6000,PDI=1.23. No PBD was observed by ¹H NMR.

What is claimed is:
 1. A method for preparing a triblock copolymer ofthe formula:

comprising: (a) contacting a cycloalkene with a chain transfer agent ofthe formula: Z—Y═Y—Z  in the presence of a metal carbene metathesiscatalyst to form a telechelic polymer; and (b) contacting the telechelicpolymer with an alkene of the formula

 in the presence of an ATRP organometallic catalyst wherein n and m areintegers; Z is an ATRP initiator and —Y═Y— is an alkenyl group; and, R′is selected from the group consisting of aryl, nitrile and C₁-C₂₀carboxylate, wherein R′ is substituted or unsubstituted.
 2. The methodof claim 1 wherein the metathesis catalyst is of the formula:

wherein: M is ruthenium or osmium; X and X¹ are either the same ordifferent and are any anionic ligand; L and L¹ are either the same ordifferent and are any neutral electron donor; R and R¹ are either thesame or different and are each independently hydrogen or a substituentselected from the group consisting of C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl,C₂-C₂₀ alkynyl, aryl, C₁-C₂₀ carboxylate, C₁-C₂₀ alkoxy, C₂-C₂₀alkenyloxy, C₂-C₂₀ alkynyloxy, aryloxy, C₂-C₂₀ alkoxycarbonyl, C₁-C₂₀alkylthio, C₁-C₂₀ alkylsulfonyl and C₁-C₂₀ alkylsulfinyl, wherein eachof the substituents is substituted or unsubstituted.
 3. The method ofclaim 2 wherein the substituent group is substituted with one or moresubstituted or unsubstituted moieties selected from the group consistingof C₁-C₁ alkyl, C₁-C₁₀ alkoxy, and aryl.
 4. The method of claim 3wherein the moiety is substituted with one or more groups selected fromthe group consisting of halogen, C₁-C₅ alkyl, C₁-C₅ alkoxy.
 5. Themethod of claim 2 wherein the substituent is functionalized with amoiety selected from the group consisting of hydroxyl, thiol, thioether,ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylicacid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy,carbamate, and halogen.
 6. The method of claim 2 wherein R is hydrogenand R¹ is selected from the group consisting of C₁-C₂₀ alkyl, C₂-C₂₀alkenyl, aryl, unsubstituted phenyl, substituted phenyl, unsubstitutedvinyl, and substituted vinyl; and wherein the substituted phenyl andsubstituted vinyl are each independently substituted with one or moregroups selected from the group consisting of C₁-C₅ alkyl, C₁-C₅ alkoxy,phenyl, hydroxyl, thiol, ketone, aldehyde, ester, ether, amine, imine,amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate,carbodiimide, carboalkoxy, and halogen.
 7. The method of claim 2 whereinL and L¹ are each independently selected from the group consisting ofphosphine, sulfonated phosphine, phosphite, phosphinite, phosphonite,arsine, stibine, ether, amine, amide, imine, sulfoxide, carboxyl,nitrosyl, pyridine, and thioether.
 8. The method of claim 2 wherein Land L¹ are each a phosphine of the formula PR³R⁴R⁵ wherein R³, R⁴, andR⁵ are each independently selected from the group consisting of aryl andC₁-C₁₀ alkyl.
 9. The method of claim 8 wherein R³, R⁴, and R⁵ are eachindependently selected from the group consisting of primary alkyl,secondary alkyl, and cycloalkyl.
 10. The method of claim 8 wherein L andL¹ are each independently selected from the group consisting ofP(cyclohexyl)₃, P(cyclopentyl)₃, P(isopropyl)₃, and P(phenyl)₃.
 11. Themethod of claim 2 wherein X and X¹ are each independently selected fromthe group consisting of hydrogen, halogen, substituted moiety andunsubstituted moiety, wherein the moiety is selected from the groupconsisting of C₁-C₂₀ alkyl, aryl, C₁-C₂₀ alkoxide, aryloxide, C₃-C₂₀alkyldiketonate, aryidiketonate, C₁-C₂₀ carboxylate, arylsulfonate,C₁-C₂₀ alkylsulfonate, C₁-C₂₀ alkylthio, C₁-C₂₀ alkylsulfonyl, andC₁-C₂₀ alkylsulfinyl, and wherein the moiety substitution is selectedfrom the group consisting of C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, and aryl. 12.The method of claim 2 wherein X and X¹ are each independently selectedfrom the group consisting of halide, benzoate, C₁-C₅ carboxylate, C₁-C₅alkyl, phenoxy, C₁-C₅ alkoxy, C₁-C₅ alkylthio, aryl, and C₁-C₅ alkylsulfonate.
 13. The method of claim 2 wherein X and X¹ are eachindependently selected from the group consisting of halide, CF₃CO₂,CH₃CO₂, CFH₂CO₂, (CH₃)₃CO, (CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO, MeO, EtO,tosylate, mesylate, and trifluoromethanesulfonate.
 14. The method ofclaim 1 wherein the cycloalkene is selected from the group consisting ofnorbornene, norbornadiene, cyclopentene, dicyclopentadiene,cyclo-octene, 7-oxanorbornene, 7-oxanorbornadiene, cyclodocene,1,3-cyclooctadiene, 1,5-cyclooctadiene, and 1,3-cycloheptadiene, whereinthe cycloalkene is substituted or unsubstituted.
 15. The method of claim1 wherein the cycloalkene is 1,5-cyclo-octadiene.
 16. The method ofclaim 1 wherein Z is selected from the group consisting of chloride,bromide, allyl chloride, allyl bromide, 2-chloro isobutyrate, 2-bromoisobutyrate, 2-chloro proprionate, 2-bromo proprionate, 2-chloroacetate, 2-bromo acetate, benzyl chloride, benzyl bromide, C₁-C₂₀ alkylbenzyl chloride, C₁-C₂₀ alkyl benzyl bromide, toluenesulfonyl chloride,toluenesulfonyl bromide, trichloromethyl, tribromomethyl,dichloromethyl, and dibromomethyl, wherein Z is substituted orunsubstituted.
 17. The method of claim 16 wherein Z is substituted witha moiety selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₁₀alkoxy, and aryl, wherein the moiety is substituted or unsubstituted.18. The method of claim 17 wherein the moiety is substituted with one ormore groups selected from the group consisting of halogen, C₁-C₅ alkyl,C₁-C₅ alkoxy, and phenyl.
 19. The method of claim 1 wherein R′ issubstituted with a substituent selected from the group consisting ofC₁-C₅ alkyl, C₁-C₅ alkoxy, and aryl, wherein the substituent issubstituted or unsubstituted.
 20. The method of claim 19 wherein thesubstituent substitution is selected from the group consisting ofhalogen, C₁-C₅ alkyl, and C₁-C₅ alkoxy.
 21. The method of claim 1wherein the alkene is functionalized with a group selected from thegroup consisting of hydroxyl, thiol, thioether, ketone, aldehyde, ester,ether, amine, imine, amide, nitro, carboxylic acid, disulfide,carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, andhalogen.
 22. The method of claim 1 wherein the alkene is selected fromthe group consisting of styrene, methyl methacrylate, n-butyl acrylate,methyl acrylate, 2-ethylhexyl acrylate, acrylonitrile, 4-vinylpyridineand glycidyl acrylate.
 23. The method of claim 1 wherein the ATRPcatalyst is of the formula MX_(p)L_(q) wherein M is selected from thegroup consisting of iron, ruthenium, nickel, and copper; X is bromide orchloride; and L is selected from the group consisting of phosphine,sulfonated phosphine, phosphite, phosphinite, phosphonite, arsine,stibine, ether, amine, amide, imine, sulfoxide, carboxyl, nitrosyl,pyridine, and thioether; and wherein p and q are integers.
 24. Themethod of claim 1 wherein the ATRP catalyst is selected from the groupconsisting of CuCl/2,2′-bipyridine, CuBr/2,2′-bipyridine,CuCl/4-4′-di-n-heptyl-2,2′-bipyridine andCuBr/4-4′-di-n-heptyl-2,2′-bipyridine.
 25. The method of claim 1 whereinthe formation of the triblock copolymers occurs in one pot.
 26. A methodfor preparing a triblock copolymer of the formula

comprising: (a) contacting a cycloalkene with a chain transfer agent ofthe formula: Z—Y═Y—Z  in the presence of a metal carbene metathesiscatalyst to form a telechelic polymer; and (b) contacting the telechelicpolymer with an alkene of the formula

wherein n and m are integers; Z is an ATRP initiator; and R′ is selectedfrom the group consisting of aryl, nitrile and C₁-C₂₀ carboxylate,wherein R′ is substituted or unsubstituted.
 27. The method of claim 26wherein the cycloalkene is 1,5-cyclooctadiene, Z is allyl chloride or2-bromoisobutyrate and the alkene is styrene or methyl methacrylate. 28.A triblock copolymer of the formula:

formed by: (a) contacting a cycloalkene with a chain transfer agent ofthe formula: Z—Y═Y—Z  in the presence of a metal carbene metathesiscatalyst to form a telechelic polymer; and (b) contacting the telechelicpolymer with an alkene of the formula

 in the presence of an ATRP organometallic catalyst; wherein n and m areintegers; Z is an ATRP initiator and —Y═Y— is an alkenyl group; and, R′is selected from the group consisting of aryl, nitrile and C₁-C₂₀carboxylate, wherein R′ is substituted or unsubstituted.
 29. Thecopolymer of claim 28 wherein the cycloalkene is 1,5-cyclooctadiene, Zis allyl chloride or 2-bromoisobutyrate, the alkene is styrene or methylmethacrylate and the ATRP organometallic catalyst isCuCl/2,2′-bipyridine or CuBr/2,2′-bipyridine.
 30. A method for preparinga copolymer of the formula:

comprising: (a) contacting a cycloalkene with a chain transfer agent ofthe formula: Z—Y═Y—Z′  in the presence of a metal carbene metathesiscatalyst to form a telechelic polymer; and (b) contacting the telechelicpolymer with an alkene of the formula

 in the presence of an ATRP organometallic catalyst wherein n and m areintegers; Z is an ATRP initiator; Z′ is hydrogen or a moiety selectedfrom the group consisting of C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₂-C₂₀alkynyl, aryl, C₁-C₂₀ carboxylate, C₁-C₂₀ alkoxy, C₂-C₂₀ alkenyloxy,C₂-C₂₀ alkynyloxy, aryloxy, C₂-C₂₀ alkoxycarbonyl, C₁-C₂₀ alkoxythio,C₁-C₂₀ alkylsulfonyl, C₁-C₂₀ alkylsulfinyl, wherein Z′ is substituted orunsubstituted; and R′ selected from the group consisting of aryl,nitrile and C₁-C₂₀carboxylate, wherein R′ is substituted orunsubstituted.
 31. A method for preparing a triblock copolymer of theformula:

comprising: (a) contacting 1,5-cyclooctadiene with a chain transferagent of the formula: Z—Y═Y—Z  in the presence of a metal carbenemetathesis catalyst to form a telechelic polymer; and (c) contacting thetelechelic polymer with an alkene of the formula

 in the presence of an ATRP organometallic catalyst wherein n and m areintegers; Z is allyl chloride or 2-bromoisobutyrate and —Y═Y— is analkenyl group; the ATRP organometallic catalyst is CuCl/2,2′-bipyridineor CuBr/2,2′-bipyridine and, R′ is selected from the group consisting ofaryl, nitrile and C₁-C₂₀ carboxylate, wherein R′ is substituted orunsubstituted.
 32. A method for preparing an SBS triblock copolymer ofthe formula: comprising: (a) contacting 1,5-cyclooctadiene with a chaintransfer agent of the formula: Z—Y═Y—Z  in the presence of a rutheniumcarbene metathesis catalyst to form a telechelic polymer; and (b)contacting the telechelic polymer with styrene in the presence ofCuBr/2,2′-bipyridine. wherein n and m are integers; Z is chloride and—Y═Y— is an alkenyl group.
 33. A triblock copolymer having no 1,2 PBDstructure in the PBD portion of the copolymer.